Unwanted or inadequate eye movements impair vision. By neurological evaluation we can sometimes localize the damage causing eye movement disorders. Our method is to combine in selected cases the best neurological evaluation possible with quantitative recording of eye movement responses to calibrated vestibular, optokinetic, and discrete visual stimuli. Eye movements are recorded by electro-oculography or infrared oculography, and now by electromagnetic search lcoils. The results are analyzed by computer. Presently we are involved in studying the adaptability of the ocular motor system to abnormal input, (presumably a cerebellar function), certain blink-saccade dyskinesias and observations on patients with cortically deprived visual systems.